The scope of the present invention is that of wedging devices for sub-munitions placed inside the envelope of a projectile.
It is known to design projectiles intended to carry sub-munitions. These projectiles can be of a type such as the artillery shell, missile, rocket or mortar projectile.
Such a projectile comprises a pyrotechnic charge which is initiated when it nears its target thereby causing the sub-munitions to be ejected from the envelope.
The sub-munitions can be of the anti-personnel or anti-tank type. When their diameter is less than that of the internal diameter of the envelope, the problem arises of how to wedge them radially with respect to the envelope.
In fact the projectile must be able to withstand the mechanical stresses caused by the transportation, handling and above all firing, without causing the deterioration of the sub-munitions.
U.S. Pat. No. 4,793,260 describes an artillery shell which carries anti-tank bomblets. The latter are wedged with respect to the envelope by means of inserts. Each insert comprises concave surfaces which come into contact with two adjacent bomblets and also comprises one convex surface which comes into contact with the internal surface of the shell envelope.
Thus, six inserts evenly distributed at an angle provide the radial wedging for seven bomblets with respect to the shell envelope.
The shell contains several "layers" of bomblets stacked axially, and each layer is wedged with respect to the envelope by a set of six inserts.
Such a wedging device presents certain disadvantages.
In fact, in order to ensure that the bomblets remain immobile, the inserts have to be of such a size that the assembly presents no radial give.
Such a tightly fitting assembly imposes the use of a press to install into the shell each group of seven bomblets together with their inserts.
So as to limit the compressive load and the stresses to which the bomblets are subjected, it is not possible to install all the "layers" of bomblets in a single operation.
The assembly must therefore be carried out "layer" by "layer", resorting at each stage to the use of a press to install the inserts.
Such an installation procedure is both long and costly. In fact, a bomblet-carrying artillery cargo shell can hold up to nine layers of bomblets which implies nine successive compression operations.